Let me answer this question by talking about one of the central and most important characters and then discussing how other characters relates to her. Florinda could be viewed as the heroine of the play, as she is definitely the only woman who is depicted as being untarnished and pure. She is of noble birth, and, at the opening of the play, as been promised by her father to Don Vincentio, an ancient nobleman. She forgets this by a trip she takes to Naples with her sister and brother. There, she has fallen in love with Colonel Belvile, an Englishman who played a key role in saving her brother's life when they were in Pamplona. Florinda would dearly love to be able to marry him.
Don Pedro, her brother, has different ideas for securing a husband for his sister, and uses the opportunity of being away from his father to give his sister to his friend, Don Antonio, a young and attractive noble. Florinda is very shocked when her brother announces she will marry Don Antonio the next day.
This announcement acts as a catalyst for Florinda, sending her out with Hellena, her more daring sister, to visit the town so that they can experience love and also so that Florinda can hopefully find Belvile and tell him of the situation that she faces. The adventures of these two sisters end in Florinda almost being raped twice, first by the Rover himself, Willmore, an English Captain, and secondly by Blunt, a country gentleman who is very unsophisticated.